dq # 6 8/18/10 measure the width of your table with something other than a ruler. my table width is...
TRANSCRIPT
DQ # 6 8/18/10
• Measure the width of your table with something other than a ruler.
• My table width is ____ _____ long.
UNIT
English vs. MetricStandard Vs. MetricUS units Vs. Metric
• Foot = King’s foot
• Inch= thumb length
• Yard= nose to your tip of your finger
QuickTime™ and a decompressor
are needed to see this picture.
When and why was the metric system invented?
• The metric system was invented in 1790
• The metric system was invented because countries were using many different systems of measurement causing confusion and lack of consistency
WHY DO WE USE THE METRIC SYSTEM?
• Almost all other countries are using the metric system
• Other countries’ companies are refusing to buy products from the U.S. if not labeled in metric units
• Scientists need a universal way to communicate data (SI Units)
Metric System
• A system of measurement used by the majority of countries on Earth based on the number 10
Scientists all over the world use the International System of Units to measure: • Length• Volume• Mass• Density• Temperature• Time
APPROXIMATE CONVERSIONS BETWEEN METRIC & US LENGTH
UNITS
• A meter is about the same length as a yard
• A meter is about three feet long
• A decimeter is about four inches long
• An inch is about 25 millimeters
• A foot contains about 30 centimeters
• A foot contains about 3 decimeters
WHAT DOES THE METRIC SYSTEM MEASURE?
• The gram measures mass or how much something weighs
• The liter measures volume which is used when measuring liquids
• The meter measures the length of an object or the distance from place to place
Key Concept: Why do scientists use a standard measurement
system? • Using SI as the standard system of measurement allows scientists to compare data and communicate with each other about their results
• Using SI measurement also allows experiments to be repeated and most importantly achieve a desired result
: SI units are based on
multiples of what number?
• SI units are based on multiples of 10
•Add a zero•Subtract a zero
The basic unit of length in the SI system is the …
• The basic unit of length in the SI system is the meter
THE METRIC CONVERSION CHART (STAIRCASE METHOD)
Kilo1000units
Hecto100units
Deka10
unitsBasic Unit Deci
0.1units
Centi0.01units
Milli0.001units
To convert to a smaller unit, movedecimal point to the right or
multiply.
To convert to a larger unit, movedecimal point to the left or divide
TRY THIS USING THE STAIRCASE METHOD
1000 mg = ______ g
Step 1: Determine if you are going to go up or down the ladder.Step 2: Determine how many steps there are from milligrams to grams.Step 3: Move the decimal point the amount of places that was determined in steps 1 & 2.
TRY THIS USING THE STAIRCASE METHOD
1000 mg = ______ g
Step 1: Determine if you are going to go up or down the ladder.Step 2: Determine how many steps there are from milligrams to grams.Step 3: Move the decimal point the amount of places that was determined in steps 1 & 2.
1
Metric System• The metric system is based on a base unit that corresponds
to a certain kind of measurement• Length = meter
• Volume = liter
• Weight (Mass) = gram
• Prefixes plus base units make up the metric system – Example:
• Centi + meter = Centimeter
• Kilo + liter = Kiloliter
Metric System
• The three prefixes that we will use the most are:– kilo– centi– milli
kilo hecto deca
Base Units
meter
gram
liter
deci centi milli
Metric System
• So if you needed to measure length you would choose meter as your base unit– Length of a tree branch
• 1.5 meters
– Length of a room • 5 meters
– Length of a ball of twine stretched out• 25 meters
Metric System• But what if you need to measure a longer
distance, like from your house to school?– Let’s say you live approximately 10 miles from
school• 10 miles = 16093 meters
– 16093 is a big number, but what if you could add a prefix onto the base unit to make it easier to manage:
• 16093 meters = 16.093 kilometers (or 16.1 if rounded to 1 decimal place)
Metric System• These prefixes are based on powers of 10. What
does this mean?– From each prefix every “step” is either:
• 10 times larger or
• 10 times smaller
– For example• Centimeters are 10 times larger than millimeters• 1 centimeter = 10 millimeters
kilo hecto deca
Base Units
meter
gram
liter
deci centi milli
Metric System
– Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length
1 centimeter = 10 millimeters
Example not to scale
1 mm 1 mm 1 mm 1 mm 1 mm 1 mm 1 mm 1 mm 1 mm 1 mm
1 cm
Metric System• For each “step” to right,
you are multiplying by 10
• For example, let’s go from a base unit to centi
1 liter = 10 deciliters = 100 centiliters
2 grams = 20 decigrams = 200 centigrams
kilo hecto deca
meter
liter
gram
deci centi milli
Metric System• An easy way to move within the metric system is by
moving the decimal point one place for each “step” desired
Example: change meters to centimeters
1 meter = 10 decimeters = 100 centimetersor
1.00 meter = 10.0 decimeters = 100. centimeters
kilo hecto deca
meter
liter
gram
deci centi milli
Metric System• Now let’s try our previous example from meters to kilometers:
16093 meters = 1609.3 decameters = 160.93 hectometers = 16.093 kilometers
• So for every “step” from the base unit to kilo, we moved the decimal 1 place to the left (the same direction as in the diagram below)
kilo hecto deca
meter
liter
gram
deci centi milli
Metric System
• If you move to the left in the diagram, move the decimal to the left
• If you move to the right in the diagram, move the decimal to the right
kilo hecto deca
meter
liter
gram
deci centi milli
Metric System• Now let’s start from centimeters and convert to
kilometers
400000 centimeters = 4 kilometers
400000 centimeters = 4.00000 kilometers
kilo hecto deca
meter
liter
gram
deci centi milli
Metric System• Now let’s start from meters and convert to kilometers
4000 meters = 4 kilometers
kilo hecto deca
meter
liter
gram
deci centi milli
kilo hecto deca
meter
liter
gram
deci centi milli
’
40 meters
Metric System• Now let’s start from meters and convert to centimeters
5 meters =
kilo hecto deca
meter
liter
gram
deci centi milli
kilo hecto deca
meter
liter
gram
deci centi milli
’
500 cm
300 m
Metric System• Summary
– Base units in the metric system are meter, liter, gram
– Metric system is based on powers of 10
– For conversions within the metric system, each “step” is 1 decimal place to the right or left
– Using the diagram below, converting to the right, moves the decimal to the right and vice versa
kilo hecto deca
meter
liter
gram
deci centi milli
Practice Time, Now you will complete the worksheet practice using the stair case
methodT. Trimpe 2008 http://sciencespot.net/
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
one-hundredth
meter
one-thousand
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
millimeter
one-hundredth
meter
one-thousand
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
millimeter
centi one-hundredth
meter
one-thousand
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
millimeter
centi one-hundredth centimeter
meter
one-thousand
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
millimeter
centi one-hundredth centimeter
none meter
one-thousand
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
millimeter
centi one-hundredth centimeter
none one meter
one-thousand
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
millimeter
centi one-hundredth centimeter
none one meter
kilo one-thousand
Complete the Table Below
Prefix Meaning Unit of Length
milli One-thousandth
millimeter
centi one-hundredth centimeter
none one meter
kilo one-thousand kilometer
Figure 2: Calculating: Measure the turtle in figure 2 from the rear of its shell to the tip of its nose. Record its length in both centimeters and
millimeters. • 10.5 cm
• 105 mm
English vs. Metric Units
Which is larger?
A. 1 liter or 1 gallon
B. 1 liter or 1 quart
C. 1 milliliter or 1 fluid ounce
1 gallon = 3.79 liters
It would take approximately 3 ¾ 1-liter bottles to equal a gallon.
1 fl oz = 29.573 ml
1 12-oz can of soda would equal
approximately 355 ml.
1 quart = 0.946 liters
Metric Units
Volume is the amount of space an object takes up.
The base unit of volume in the metric system in the liter and is represented by L or l.
Standard: 1 liter is equal to one cubic decimeter Metric Units
1 liter (L) = 1000 milliliters (mL)
1 milliliter (mL) = 1 cm3 (or cc) = 1 gram*
Which is larger?
A. 1 liter or 1500 milliliters
B. 200 milliliters or 1.2 liters
C. 12 cm3 or 1.2 milliliters*
Click the image to watch a short video
about volume.
* When referring to waterLiter Image: http://www.dmturner.org/Teacher/Pictures/liter.gif
Measuring Volume
Top Image: http://www.tea.state.tx.us/student.assessment/resources/online/2006/grade8/science/images/20graphicaa.gif
Bottom Image: http://morrisonlabs.com/meniscus.htm
We will be using graduated cylinders to find the volume of liquids and other objects.
Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water.
What is the volume of water in the cylinder? _____mL
What causes the meniscus?
A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on the sides.
Measuring Liquid Volume
Images created at http://www.standards.dfes.gov.uk/primaryframework/downloads/SWF/measuring_cylinder.swf
What is the volume of water in each cylinder?
Pay attention to the scales for each cylinder.
Measuring Solid Volume
Click here for an online activity about volume. Choose Lessons Volume & Displacement
10 cm
9 cm
8 cm
We can measure the volume of regular object using the formula length x width x height.
_____ X _____ X _____ = _____
http://resources.edb.gov.hk/~s1sci/
R_S1Science/sp/en/syllabus/unit14/new/
testingmain1.htm
We can measure the volume of irregular object using water displacement.
Amount of H2O with object = ______
About of H2O without object = ______
Difference = Volume = ______